Very-low-level waste

Very-low-level waste mostly comes from dismantling of nuclear facilities and conventional industrial plants in various sectors (chemicals, metallurgy, energy production, etc.) which used naturally radioactive materials. It also originates from clean-up and rehabilitation operations on sites which were formerly polluted by radioactivity. Around 50% of this waste is “common industrial waste” (scrap metal and plastics), 40% is inert waste (concrete, bricks, earth, rubble, etc.) and 10% is “special waste” made of materials such as sludge and, in some cases, pulverulent waste (ashes, etc.). Very-low-level waste has a radioactivity level close to that of naturally occurring radioactivity (between 1 and 100 Bq/g). It contains short-lived and/or long-lived radionuclides. This waste is managed at the Andra CSTFA disposal facility located in the Aube district.

Treatment and conditioning

Before being disposed of, some VLLW is subject to special processing. Plastic and metallic waste is compacted to reduce its volume. Liquid waste, such as contaminated water or sludge, is solidifi ed and then stabilised. Because of the nature of this waste and its low level of radioactivity, it is packaged in metal drums or “big-bags”, primarily to facilitate its handling.

Management

Since 2003, very-low-level waste has been disposed of at the Andra CSTFA disposal facility, the fi rst disposal facility in the world for this type of waste. Situated in the Aube district, it is designed to accommodate 650,000 m3 of waste. Once conditioned, waste batches are labelled and emplaced in successive horizontal layers (around ten on average) inside several metres deep disposal vaults excavated in clay. Once the disposal vault is fi lled, it is defi nitely closed and then capped with a compacted clay layer. This compaction process aims at restoring its initial low-permeability to the clay material. In order to get the most out of the repository capacity and reduce volumes to be disposed of, waste generators must take action to optimize waste processing and conditioning.

VLLW existing at the end of 2007:

• 20.1% of the total volume of French radioactive waste
• 0.000003% of the total radioactivity of French radioactive waste